In the US I would have to say New York, so many things to see. Just an amazing city that should be seen by all. Florida, lots to do, plus Disney World. California, beautiful place, nice beaches, amazing houses and Disneyland. Also, Alaska. Just a beautiful place to visit. Mountains, glaciers, snow, wildlife, etc. Amazing to say the least.
Out of the U.S. Paris, nothing else needs to be said. And then probably St. Thomas (U.S. virgin island, but feel so distant) is a beautiful island. There is so many different shops to visit and such a wide array of products to purchase. The beaches are beautiful. Plus it is a great place because you could visit so many different island in the area and you could visit most or all in one day.
I love taking cruises because you can go to so many different ports and see so many different things. I especially love long Alaskian cruises where you visit all the major ports on the border of the state. There is also some cruises where you get a guided tour included at each port. You can learn so much and see so much it is amazing.